The VHA and the Indian Health Service (IHS) executed Memoranda of Understanding (MOU) in 2003 and 2010 to jointly improve access to healthcare and optimize outcomes for American Indian and Alaska Native (AIAN) Veterans, which included innovative Home Based Primary Care (HBPC) projects to serve AIAN Veterans who live on rural American Indian reservations. These pilot projects represent a natural laboratory to study how partnerships and co-management strategies can reduce geographic and resource barriers in rural areas in an effort to improve access to healthcare as well as quality of care. Although these projects are cited as examples of collaborations in the 2010 MOU, the range of variation among projects and the patient and organizational outcome correlates are currently unknown. Our immediate goals are to document the innovation models and determine their respective patient-level and organizational-level outcomes with the aim of identifying best practices and models or integrated or co- managed care that might be more widely disseminated, while making new discoveries and adding to the existing knowledgebase. We approach this observational multiple case study using mixed methods in two clearly defined phases. Phase I uses qualitative methods and an emergent research design to identify and characterize variation in the HBPC pilot programs and identify key barriers and facilitators to clinical collaboration. Results of this descriptive phasewill be represented as categorical variables in Phase II outcome analyses. Phase II uses quantitative methods in a quasi-experimental pre/post design. Our comparative analyses use a non-equivalent control group design between the HBPC intervention population and a propensity matched sample. In both phases, we will be guided by a national advisory committee who will serve as a panel of experts to link research findings to policy and practice. Study Question 1 (Phase I): What are the organizational contexts and processes of care that account for variation in HBPC models that have been implemented as collaborative partnerships between VHA and IHS and/or Tribe healthcare organizations? Study Question 2 (Phase II): What are the patient-level outcomes of the pilot HBPC projects in rural areas? H1. Establishing local HBPC programs on or near rural American Indian reservations increases enrollment in VHA by AIAN Veterans. H2. The intervention population has lower hospital admission rates (i.e., admission, re-admission, and bed days of care) than a propensity-matched sample having usual care. H3. The intervention population has lower rates of emergency department visits than a propensity-matched sample having usual care. Study Question 3 (Phase II): What are the organizational outcomes of the pilot HBPC models in rural areas? H4. Costs to VHA are offset by patients' participation in all VHA-IHS/Tribal HBPC program models. This project is expected to have immediate benefits by providing insights into how VHA, Tribes and IHS can work together most successfully to meet VHA's policy goals for 1) Tribal consultation and 2) improving healthcare access and health outcomes of AIAN Veterans in collaboration with IHS and 3) improving access to healthcare in rural areas. In addition, these insights may suggest new opportunities for expansion of T21 initiatives for primary and extended care in rural areas, where 41% of enrolled Veterans reside. Like other new VA initiatives, the introduction of new clinics and processes may lead to an expansion of clinical services. Therefore, the long-term aim of this project is to implement best practice models for co-management of patients across federal healthcare organizations.